Dough mixer with metering device

ABSTRACT

In a dough mixer for preparing dough, the essentially cylindrical chamber with horizontal axis within which kneading elements ( 4, 4   c   , 4   b ) rotate coaxially or parallel to this axis, between two casing surface sections ( 1   a ) with the same casing line, two level surface sections ( 1   b   , 1   c ) which are essentially formed by the surface of sliding ( 2   b   , 3   b ) blades ( 2, 3 ) with upper charging opening ( 2   a ) and lower discharging opening ( 3   a ) in closed position, and the aforementioned surfaces ( 1   a   , 1   b   , 1   c ) turn into two front, coaxial, separated circular surfaces ( 1   e   , 1   f ) via rounded areas ( 1   g ) with the largest possible radius, such that, together with the rotating ( 4   a ) kneading element ( 4, 4   c   , 4   d ), which likewise has very round forms, they enable the preparing and compressing of dough and rolling into balls of an individual dough portion that is discharged without residue of ingredients or dough. The metering device for charging the dough mixer with volumetric calibrated and the most homogeneous portion of flour-like ingredients has a vertical shaft ( 8 ) that rotates coaxially ( 8   a ) to the cylindrical container ( 5, 5   a   , 5   b ), which drives stirring elements ( 7   a   , 7   b ), a distribution cone ( 7 ) and a metering disk ( 9   a ) with metering holes ( 9   a ) positioned on the rim that are equidistant both from one another and from the axis. The container of the metering device is divided on the inside by an annular, funnel-like partition ( 6 ) into an upper container and a lower, smaller region for the metering mechanism.

SPECIFICATION

[0001] Dough mixers for producing dough used in preparing foods areknown which utilize the function of one or two screw conveyors, ofrotating mixing arms within fixed or rotating containers with verticalor angled axis, or of kneading elements rotating within a closed housingwith a horizontal axis.

[0002] The specific level of technology is based on this last type ofdough mixer, which thus uses the function of mixing elements rotatingwithin a closed casing on a horizontal axis.

[0003] The U.S. Pat. No. 5,486,049 (apparati for mixing liquidsubstances) refers to a device for mixing liquid substances of varyingdegrees of viscosity. The stirring element of this device comprises aplurality of rungs that are arranged between two coaxial disksequidistant from each other and to their rotational axis.

[0004] The U.S. Pat. No. 4,630,930 (high-speed batch mixer) publishes amethod and device for producing a portion of dough. The device comprisestwo coaxial chambers within which there are separate work phasesperformed by separate and different mixing or kneading elements. Theingredients for preparing the dough are introduced from above into thefirst chamber, where they are thoroughly mixed and then transported intothe second chamber. In the second chamber they are kneaded by a kneadingelement that comprises parallel rungs, which are attached at both endsto corresponding radial arms that extend at the same angles and rotateabout a common axis. The technical features of the second devicerequires a previous thorough mixing in a mixing chamber that isseparated from the kneading chamber; the casing line of the insidecasing surface of the mixing chamber and of the kneading chamber have arotational axis that is coaxial with the rotational axis of the kneadingelement.

[0005] The U.S. Pat. No. 5,322,388 (dough mixer) publishes a device forpreparing dough which comprises a cylindrical chamber with a horizontalaxis having in its upper region an opening for charging by free fall theingredients that are used for preparing the dough, and in its lowerregion a closeable opening for discharging the prepared dough. Theoperation within the chamber takes place in the chamber's lower regionby using several equidistant agitator blades on the same drive shaftwith a rotational axis that is displaced but parallel to the chamberaxis. The kneading chamber of this device can be opened because thedisk-shaped vertical wall together with the agitator blades and the wallof the casing surface can be moved axially to the second vertical,disk-shaped wall, on which a scraper is located together with thecorresponding drive motor.

[0006] There are other smaller mechanical devices for preparing dough inthe household; generally, they comprise a cylindrical container with avertical axis within which one or more agitator blades operate on asingle drive shaft that is attached coaxially to the container axis.

[0007] All of these known devices are not designed for preparingindividual dough portions per each work cycle within relatively shortperiods of time and by charging with ingredients in individual portions;further, they do not provide that every individual mixed dough portionthat is rolled into a ball and is ready for shaping and baking can bedischarged without leaving ingredients or dough residue inside thedevice. The known devices are also not designed to perform a periodic,completely automatic sterilization of the kneading chamber and itskneading elements.

[0008] The problem is also known that the charging of the kneadingdevices with relative exact volumetric metering of the flour orflour-like or dust-like ingredients, which are more or less hydroscopic.Such problems are based on the tendency that flour-like material formsaccumulations or agglomerates inside the container, that varying thematerial volume above the metering mechanism strongly affects themetering process and that it is difficult to achieve an even fillingand/or emptying of the metering chamber.

[0009] The object of the invention is to create a dough mixer asdescribed above that has a simple and compact design, can beautomatically sterilized, has an essentially cylindrical chamber withhorizontal axis in which a kneading element operates with horizontallyrotating axis, due to direct charging of the chamber with pre-meteredingredients per work cycle, to create in a short period of time aportion of dough which then is finally discharged as a mixed individualportion in the form of a ball and ready-made for subsequent shaping,garnishing, and baking or deep-freezing.

[0010] To attain the object of the invention, the invention proposescreating a housing with an inner chamber that is essentially cylindricaland has in its upper section, which corresponds to the charging regionfor the flour-like and possibly also liquid ingredients, as well as inthe lower section, which corresponds to the discharge region, a surfacearea that runs parallel to the chamber axis and turns into the chambercasing surface. Within this chamber operates a rotating kneading elementaccording to an axis that runs coaxially or parallel to the chamberaxis, and this element comprises at least one arm formed with one endattached radially to the end of a drive shaft, and on the other end ofwhich at least one fixed bearing pin is attached cantelever with an axisrunning parallel to the rotational axis of the drive shaft; a freelyturning sleeve is placed by means of a recessed hole on top of thisbearing pin with rounded terminal ends on both sides. As an advantageousfeature are two arms extending radially from the same drive shaft, whichare oriented to each other longitudinally or are in the same level butare at a certain angle to each other, and each of these arms carries abearing pin with a rotating sleeve placed on top parallel to therotational axis, preferably with a different distance to the rotationalaxis of the drive shaft. While these bearing pins, which are equippedwith rotating sleeves, are in motion, the dough is compressed, rolledand rolled thin repeatedly in particular in the lower region of thechamber with the level surface section that turns into the curved casingsurface. If a plurality of these sleeves are operated, they can havevarying outside diameters, cross-sections, and shapes depending on theconsistency of the dough being produced and/or the properties of theingredients and/or the percentage of liquid ingredients. The inventionprovides further for the interchangeability and/or the change in thenumber of the sleeves mentioned, depending on the properties of theingredients and/or the dough that is being prepared.

[0011] Due to the charging of the chamber with dry flour-likeingredients, the kneading element carries out the work phase with thepurpose of homogenizing and aerating the dried ingredients by rotatingat a relatively high speed in order to achieve a better thorough mixingof the ingredients thus introduced, and their preparation for thesubsequent introduction of liquid ingredients, which ensures that theyare evenly absorbed, and the dough agglomerate is then created with amarkedly reduced rotational speed; by further reducing the speed, amixing and homogenization of the dough mass is achieved, which then,upon further reduction in rotation speed, is compressed and rolled intoballs, which as such are discharged in part due to gravity by openingthe discharge opening in the region corresponding to the lower levelsurface section of the chamber.

[0012] According to the invention, the individual inner surfaces andsurface areas of the dough mixer chamber have surface transitions withrounded areas with the largest possible radius, including the rotatingarms or the sleeves of the kneading elements, all have rounded forms,and thus the chamber space is free of edges or recesses on which doughresidue could stick that is not discharged along with the individualportion, due to the process by which the dough is kneaded and rolledinto balls. After rolling into balls and discharging, the chamber andthe kneading elements are thus free of any residue from the dough andingredients. This form further allows them to be sterilized by means ofhot air, through which small amounts of sticky dough residue are removedin the air current due to the drying process and the application ofpressure.

[0013] The front surface of the chamber, which is across from the secondfront surface from which the drive shaft for the kneading elementprojects, can have a level, conical, more or less rounded form thatprotrudes against the drive shaft, with its axis extending coaxially tothe rotational axis of the drive shaft or parallel to it preferably inthe upper level of the chamber. By means of a distinctive conical ornose cone form, the rotating sleeves of the kneading element can rollthe dough thin even with this shape. According to this invention,further, the housing wall that corresponds to this front interiorsurface with more or less distinctive shape can be replaced by anotherhousing wall, in order to change the volume of the chamber by changingthe distance between the front circular surfaces; in this case, thesleeves on the kneading element are also replaced by sleeves with theappropriate longitudinal extension.

[0014] It is advantageous that the liquid ingredient(s) for preparingthe dough is/are introduced through one or more openings in the centralregion at the front wall across from the wall with the drive shaft.

[0015] In terms of the volumetric metering of the dry, flour-likeingredients, the invention proposes that a metering device be located inthe region of the charging opening that is equipped e.g., with slidingblades, which essentially comprises a cylindrical container withvertical axis for the flour, and this container is equipped with avolumetric metering mechanism at its bottom. According to thisinvention, the container has inside in its lower region an annular,funnel-like partition, and the point of a distribution cone extendsthrough the partition's central, circular opening so that an annularpassageway is free for the flour. The container has at the bottom ametering sieve above which beaters move during the rotation of thedistribution cone, which is driven by means of a vertical central shaftby a motor, in order to transport the flour through the metering sieveand through the holes which are positioned equidistant to the rotationalaxis on the metering disk located beneath it. The metering disk islocated on the bottom disk, which is connected to the cylindrical wallof the container and which has an hole in the region of the chargingopening of the dough mixer attached beneath it, through which the flourfalls from the metering holes at the rotating metering disk and throughthe charging opening into the chamber of the dough mixer.

[0016] The invention does not exclude the possibility that the doughmixer, according to this invention, is fed from a metering device thathas features other than those proposed by the invention, or from adevice which charges with a pre-measured portion.

[0017] The invention will be explained in more detail below based on apreferable exemplary embodiment that is represented schematically in theattached drawings of a dough mixer according to the invention that ischarged according to the invention that prepares individual portions of130-260 g within 10-15 seconds, which is especially suitable forpreparing flat breads or pizzas.

[0018]FIG. 1 shows in cross-section a dough mixer according to theinvention during the charging phase, which is linked to a meteringdevice according to the invention, showing a sectional view according tothe plane of section 1:1 in FIG. 2, which plane runs through the axis ofthe drive shaft of the metering device.

[0019]FIG. 2 shows the dough mixer according to the invention and asshown in FIG. 1 together with a metering machine in sectional viewaccording to the plane of section II-II shown in FIG. 1.

[0020] According to this invention, the dough mixer for preparingindividual portions comprises a housing 1 with an inner chamber and akneading element 4, 4 c, 4 d, containing a charging opening 2 a and adischarging opening 3 a, 1 d, with corresponding blades 2, 3. Theessentially cylindrical chamber with horizontal axis is delimited by alevel, circular surface 1 e from which a shaft 12 a extends coaxially,by a circular surface 1 f corresponding to the aforementioned but with aconical form projecting slightly into the chamber, by two curvedsurfaces 1 a with a casing line equidistant from the chamber axis, by anupper level surface section 1 c that essentially corresponds to theregion of the charging opening 2 a, and by a lower level surface section1 b, which is larger than the upper one and corresponds to the region ofthe discharging opening 1 d, 3 a.

[0021] The kneading element comprises an arm 4 which is fastened on itsfront side at the end of the drive shaft 12 a that extends into thechamber; at each of the ends of arm 4 a pin 4 c is fastened having anaxis running parallel to the rotational axis of the drive shaft 12 a,and a freely turning 4 b sleeve 4 d with a rounded, hemispherical ornose cone-shaped terminal area is placed on each of pins 4 c by means ofa recessed hole. Arm 4 of the kneading element is fastened to driveshaft 12 a, off-center relative to the center line of thetransverse-extending arm, such that two pins 4 c with sleeves 4 dattached to it turn with varying radius about the rotational axis ofdrive shaft 12 a, which is driven by the electric motor 12 at varyingrotational speeds and changing rotation directions.

[0022] Charging opening 2 a for the introduction 14 b of the flour-likeingredients in the upper region and discharging opening 3 a, Id for theindividual portions of dough balls in the lower region, are providedwith sliding blades 2, 3, which for example are moved 2 b, 3 b bypneumatic cylinders 2 c, 3 c without excluding the use of rotatingblades and other drives.

[0023] Liquid ingredients are charged via a single hole 13 or viaspecific holes for each of the liquid ingredients, which holes areconical and all preferably disposed on the disc-shaped wall 11 in theregion within the track of sleeve 4 d, which turns with smaller radiusabout shaft 4 a. Same hole 13 can be used for blowing in hot air toclean and/or sterilize the chamber and rotating kneading elements 4, 4c, 4 d. The method for preparing dough with the dough mixer according tothis invention, has essentially the following phases:

[0024] Charging 14 b with flour- or dust-like ingredients,

[0025] Homogenization and aeration of the flour- and/or dust-likeingredients,

[0026] Charging 13 a with liquid ingredients,

[0027] Preparing the dough,

[0028] Rolling the dough thin,

[0029] Compacting and rolling the dough into balls

[0030] Discharging the individual dough portions

[0031] Following production of a pre-programmed number of dough portionsand based on the production intervals, the chamber of the dough mixer iscleaned and sterilized with hot air.

[0032] Charging 14 b with flour-like and/or dust-like ingredients is byfree fall through charging opening 2 a equipped with sliding blades 2,which is driven 2 b by pneumatic cylinder 2 c. The construction andoperation of the metering device, in accordance with the invention, withdischarging opening 5 e, corresponding to charging opening 2 a of thedough mixer with which it is connected, will be explained later.

[0033] The flour-like and dust-like ingredients are homogenized andaerated by rotating kneading element 4, 4 c, 4 d at a relatively highspeed (approx. 2,500-3,000 rpm) that creates a favorable dispersion ofthe ingredients due to the special form of the chamber and kneadingelements, wherein the particles of the dry ingredients are prepared foreven absorption of the liquid ingredients following charging 13 a.

[0034] The dough mixture is prepared by rotating 4 a kneading element 4,4 c, 4 d at a lower rotation speed (approx. 950-1,400 rpm); this phaseis followed initially by the formation of little dough clumps, which arethen rolled together by the repeated action of rotating 4 b sleeves 4 d.

[0035] The dough is then prepared by rotating kneading element 4, 4 c, 4d at an even lower rotation speed (approx. 850-920 rpm); especially inthis phase, the dough is repeatedly and intensely rolled out and rolledthin by the turning 4 b sleeves 4 d, particularly at lower level surfacesection 1 b. The formation of a compact, balled together dough massfollows at an even lower rotation speed (approx. 700-820 rpm), thustaking on the form of a “dough ball” at the end of this phase.

[0036] The “dough ball” is discharged by centrifugal force via therotating kneading element and by gravity through discharging opening 3a, which is opened by activating 3 b blade 3 by means of pneumaticcylinder 3 c.

[0037] During the various work stages, in particular during compacting,rolling out, and balling together the dough, it can be advantageous tomake one or more changes in rotational direction 4 a of kneading element4, 4 c, 4 d. Liquid ingredients can be charged 13 a more or less instages and while kneading element 4, 4 c, 4 d is rotating. For cleaningand/or sterilization of the chamber by injecting hot air, the cool airof motor 12 that drives 12 a the kneading element or the air that isdiverted from the pneumatic system can be used, the air being heatedprior to its injection into the chamber.

[0038] The volumetric metering device for the dry flour-like ingredientsaccording to the invention comprises a cylindrical container 5, 5 a, 5 bwith vertical axis, a distribution cone 7 with beaters 7 a, 7 b rotating8 a coaxially to the container axis, and a metering disk 9 with meteringholes 9 a on the rim which form the volume units for creating a totalportion of flour 14 to be charged 14 b into the dough mixer in order togenerate a single portion of dough.

[0039] Cylindrical vertical wall 5 is sealed with bottom plate 5 b,which provides a seating 5 c for the bottom end of a vertically rotating8 a shaft 8 that is centrally seated 5 d in cover plate 5 a. The upperend of shaft 8, which extends beyond the cover plate 5 a, is equippedwith a pulley 8 a driven by the belt 8 b of a motor 11 attached to thecontainer. Shaft 8 can naturally be driven in other ways and by othersources of power. Inside, in the lower region, the container is equippedwith an annular, funnel-like partition 6 for directing flour 14 in thedirection of the container axis. The upper region of a distribution cone7, which is connected to drive shaft 8, extends through the centralopening in partition 6 such that an annular duct 6 c results for flour;beaters 7 b that extend down from the cone 6 and move closely abovepartition 6 cause flour 14 to pass through 14 a. Partition 6 and cone 7prevent variations in the fill level of flour 14 and thus the weightabove partition 6 from having an affect on the metering mechanismdisposed beneath. This mechanism comprises metering disk 9 with holes 9a on rim that rotates together distribution cone 7 and drive shaft 8;individual holes 9 a, which are equidistant to the axis of rotation ofthe disk, represent with their volume the metering unit for creating thecharging amount. Above metering disk 9 is a sieve 10 equipped with ducts10 a through which the flour is moved through at least one beater 7 cwhich sticks out from cone 7, and turns with drive shaft 9, and movesabove sieve 10. On the underside, metering disk 9 lies on top of bottomdisk 5 b of the container. Bottom disk 5 b has an outflow through hole 5c that corresponds in diameter to holes 9 a on metering disk 9 or is ofa greater diameter and in the region of the passage of these holes.Practice has shown that the construction described here allowsvolumetric metering that is independent of the fill level in thecontainer, the moisture level and other physical properties of thecontents, which metering is sufficiently constant and can be varied byone or more volume units that are determined by individual holes 9 a onmetering disk 9. This feature of the metering device is fundamental forachieving homogeneity in the individual dough portions, which requirescharging with calibrated, homogeneous ingredients and attains this aboveall by assuring that the mixture does not put weight on the meteringmechanism in a single casing 5, 5 a, 5 which is fed via a relativelynarrow annular duct 6 c and, affected by simultaneous mixing motions inthe container region above the partition 6 and in the emptying region ofthe metering holes 9 a and at the metering disk 9. Naturally, the amountof flour 14, which moves through annular duct 6 c, must be at least asgreat, preferably somewhat greater than the amount which is fed to thedough mixer for the purpose of maintaining the individual portion ofdough.

[0040] The invention does not exclude the possibility of linking themetering device according to the invention to a dough mixer or anotherdevice that does not correspond to the dough mixer according to theinvention.

1. A dough mixer for the production of dough for baked goods that isequipped with a metering device for flour-like ingredients, of the kindwith closed housing with horizontal axis in which a kneading elementoperates with rotational axis that is coaxial or parallel to the housingaxis, characterized in that chambers of the dough mixer inside a housing(1) having two inner, essentially circular, juxtaposed, coaxial andseparated surfaces (1 e, 1 f) between which two casing surface sections(1 a) extend which run in an arc along the same casing line and changein the upper and lower region into a flat surface section (1 b, 1 c), ofwhich each is at least partially formed by the surface of a sliding (2c, 3 c) blade (2,3) in its closed position; that along the perimeter onboth circular surfaces (1 e, 1 f) a cross piece (1 g) with largerounding-off radius is provided to the casing surface sections (1 a) andto the level surface sections (1 c, 1 b), and that the circular surface(1 f) which is across from the flat circular surface (1 e) from whichthe drive shaft (12 a) extends for the kneading element (4, 4 c, 4 d)has a slight conical or domed form that projects out into the innerchamber, coaxially to the rotational axis of the kneading element (4, 4c, 4 d).
 2. The dough mixer with metering device according to claim 1,characterized in that the circular surface (1 f) in the chamber of thedough mixer, which from the circular surface (1 e) from which the driveshaft (12 a) extends for the kneading element (4, 4 c, 4 d), has adistinctive conical, nose cone-shaped, or cylindrical form withhemispherical end that is coaxial or parallel to the rotational axis ofthe kneading element (4, 4 c, 4 d).
 3. The dough mixer with meteringdevice according to claim 1, characterized in that the circular surface(1 f) which from the circular surface (1 e) from which the drive shaft(12 a) extends for the kneading element (4, 4 c, 4 d) has one or moreholes (13) for the supply of liquid ingredients and that the hole orholes (13) are provided in a central region of the circular surface (1f), which is within the circular track of the ends of the kneadingelement (4, 4 c, 4 d).
 4. The dough mixer with metering device accordingto claims 1 through 3, characterized in that the chambers of the doughmixer together with the kneading element (4, 4 c, 4 d) are occasionallysubjected to moving hot air which is introduced through a separate holeor nozzle or via one or more holes (13) used to charge liquidingredients and which exits through a discharging opening (3 a, 1 d),and that this air is generated by the drive motor (12) of the doughmixer or from a pneumatic system and is heated prior to entry in orderto sterilize the chamber and the kneading element, and loosens any bitsof dough or leftover ingredients, and transports them by means of theexiting stream of air.
 5. The dough mixer with metering device accordingto claim 1, characterized in that the kneading element of the doughmixer comprises an arm (4), which extends radially from the end of thedrive shaft (12 a) and from the free end of which arm is attached afixed pin (4 c) with an axis running parallel to the rotational axis ofthe arm, on which is placed a cylindrical sleeve (4 d) by means of anaxial recessed hole and that both terminal regions of the sleeve (4 d)are rounded-off, round-ended, or nose cone-shaped.
 6. The dough mixerwith metering device according to claim 1 and partially according toclaim 2, characterized in that the kneading element comprises two ormore arms (4) which radially are at some distance from the end of thedrive shaft (12 a), possibly at various angles to each other and on eachend of which is attached a fixed pin (4 c) with a longitudinal axisrunning parallel to the rotational axis of the arms (4) on which sleevesare placed of possibly different outside diameter and/or differentforms, and that the axes of the individual pins (4 c) on each of thearms (4) are not equidistant to the common rotational axis.
 7. The doughmixer with metering device according to the claims from 1 to 6,characterized in that the wall with its front side circular surface (1f) of the chamber of the dough mixer, which stands opposite to thecircular surface (1 e) from which the drive shaft (12 a) for thekneading element (4, 4 c, 4 d) extends, is replaceable with walls thatare suitable for changing the distance between both of the front sidesurfaces (1 e, 1 f) and that depending on this change the sleeves (4 d)can also be substituted.
 8. The dough mixture with metering deviceaccording to the protective claim 1, characterized in that the meteringdevice mounted on the dough mixer with vertical axis contains a dustregion for the flour (14) in the upper region, and a metering mechanismwithin the same cylindrical container (5, 5 a, 5 b) in the lower region,and the stirring elements (7 b) for the dust region of the flour,together with the stirring elements (7 a) of the metering mechanism areactivated by a shaft (8) that is shared coaxially with the containeraxis and that this shaft, in addition, is connected with a distributioncone (7) for the flour for the metering region and with a metering disk(9) with metering holes (9 a) on the rim that are equidistant both fromone another and to the rotational axis.
 9. The dough mixer with meteringdevice according to claims 1 and 8, characterized in that in thecontainer of the metering device, which the dust region for the flour(14) relating to the metering region is horizontally subdivided by anannular, funnel-like partition (6) through which the central opening ofthe upper part of the distribution cone (7) extends in order to form anannular duct (6 c) for the flour (14), and that at least one stirringelement (7 b) operates which extends radially from the distribution cone(7) near the upper surface of the partition (6).
 10. The dough mixerwith metering device according to claims 1, 8 and 9, characterized inthat the metering mechanism in the metering device, which comprises ametering disk (9) with continuous metering holes (9 a) driven (8 a) bythe same shaft (8) that drives the distribution cone (7) and thestirring elements (7 a, 7 b), that this rotatable metering disk ispositioned between the fixed, level bottom plate (5 b) of the containerof the metering device and an annular, fixed sieve (10), and that thebottom plate (5 b) forms the lower level and the sieve (10) covers theupper ring region of the metering disk (9) free of the distribution cone(7) and that the bottom plate (5 b), in the region of the track of themetering holes (9 a) of the metering disk (9), has a continuous outflowopening (5 e).
 11. The dough mixer with metering device according toclaims 1, 8, 9, 10, characterized in that the sieve (10) within themetering device, which covers the metering disk (9) at least in thetrack region, in the outflow region which is defined by the outflow hole(5 e) on the bottom plate (5 b), has no ducts (10 a) for the flour, andthat at least one stirring element at some distance from thedistribution cone (7), while its rotation (8 a) passes close to thesurface of the sieve.
 12. The dough mixer and metering device accordingto the claims 1 through 11, characterized in that both of the devicescan also function independently of each other, and the dough mixer witha known metering device or the metering device can be coupled with aknown kneading device.